Which of the following is an example of a descriptive study?

Correct Answer: A

Rationale: Case reports (A) describe individual cases (e.g., new disease). B, C, and D are analytical or experimental.

Correct Answer: C

Rationale: A confounder (C) links exposure and outcome (e.g., age in smoking-cancer). A is the exposure, B is the outcome, D is bias.

Correct Answer: C

Rationale: Informed consent excludes exact results (C) as they’re unknown pre-study. A, B, and D are required (e.g., purpose, risks, voluntariness).

Correct Answer: B

Rationale: High specificity (B) confirms diagnosis (e.g., few false positives, SpPin). A needs sensitivity, C is sensitivity, D is broad.

Correct Answer: B

Rationale: Primary prevention (B) stops disease before it starts (e.g., vaccination). A is secondary, C and D are tertiary.